Hi, Few typos spotted
03/07/2017 05:57, Qi Zhang: > --- a/doc/guides/nics/i40e.rst > +++ b/doc/guides/nics/i40e.rst > @@ -447,3 +447,30 @@ It means if APP has set the max bandwidth for that TC, > it comes to no > effect. > It's suggested to set the strict priority mode for a TC that is latency > sensitive but no consuming much bandwidth. > + > +VF performance is impacted by PCI extended tag setting > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > + > +To reach maximum NIC performance in the VF the PCI extended tag must be > +enabled. The DPDK I40E PF drvier will set this feature during initialization, drvier -> driver > +but the kernel PF driver does not. So when running traffic on a VF which is > +managed by the kernel PF driver, a significent NIC performance downgrade has significent -> significant > +been observed (for 64 byte packets, there is about 25% linerate downgrade for > +a 25G device and about 35% for a 40G device). > + > +For kernel version >= 4.11, the kernel's PCI driver will enable the extended > +tag if it detects that the device supports it. So by default, this is not an > +issue. For kernels <= 4.11 or When the PCI extended tag is disabled it can be When -> when > +enabled using the steps below. > + > +#. Get the current value of the PCI configure register:: > + > + setpci -s <XX:XX.X> a8.w > + > +#. Set bit 8:: > + > + value = value | 0x100 > + > +#. Set the PCI configure register with new value:: > + > + setpci -s <XX:XX.X> a8.w=<value>
